The Mercedes-Benz SLS AMG was instantly captivating for its looks and soaring gullwing doors. Now comes the roadster variant, which Mercedes is previewing in these shots illustrating the car during testing. The car will officially bow in September at the Frankfurt motor show.

The roadster will pack 563 hp and arrives in the United States late this year as a 2012 model, the culmination of a three-year development period during which extensive attention was paid to rigidity and handling. Mercedes engineers were unwilling to sacrifice the drive character of the coupe and say the body shell of the convertible comes in at 536 pounds--just five pounds more than the coupe.

The soft top, which is up in these pictures, can be electrohydraulically closed at up to 31 mph and employs a three-layer fabric top. Mercedes added reinforcements behind the seats to bolster the rollover protection system.

Additionally, the car was subjected to 20,000 closing cycles while stationary and 2,500 while in motion, a test Benz claims is used for all of its new convertibles.